by Jeremy Schrag
Does anybody remember when Chrysler bought a failing car company called AMC from Renault? I'll wager a lot of you do. Back in the 1980s, Renault, then owner of the American Motors Corporation, got tired of trying to compete in the North American market. Under the terms of the sale, Chrysler would sell Renault's cars for them. After a name change from AMC to Eagle, this is exactly what they did when the Eagle Premier made its appearance; when Premier failed to meet the sales volume requirements, the identical Dodge Monaco was added.
These cars needed fancy sound systems, however, and none of Chrysler's existing offerings were of the correct form factor for the dash. Chrysler's usual decks were 1.5 DIN form factor, while the Premier and Monaco needed strictly DIN sized offerings. What to do?
It didn't take long to work something out. Chrysler already had a pretty good thing going with Mitsubishi, with that company having supplied some of their finest head units for years by this time, and Mitsubishi was quick to make something happen.
Mitsubishi's efforts resulted in the premium deck from an Eagle Premier, an optional unit with a sophisticated seven band equalizer with memory functions, an advanced cassette deck with music search functionality, and of course the usual AM/FM tuner. It is housed in two DIN sized enclosures, both of which I am going to be looking at today. Thanks to Bob Rebello for supplying these units for me to look at.
This unit, model 36001571, was an intermediary option; a CD player was optional as well.
We're going to start by having a look at the amplifier/EQ module. I'll try to show you everything I can about the maintenance of this unit, so that you can attempt some repairs yourself. Be warned, however... this is perhaps the most sophisticated 1980s head unit combo I have ever seen in any Chrysler product. It is a close cousin of the Chrysler/Infinity II cassette head unit, only it's even more complex and failure prone. This one is barely functional at all. It appears to turn on, but there is no sound and the LCD displays do not light up.
More than likely, this being a Mitsubishi product from the 80s, we will find a ton of bad solder joints in both modules. Warm up your soldering iron, kids, I can just about guarantee you will be needing it.
A quick word about the label (that shows this is model 36001571). It is always nice when these labels hold an accurate pinout diagram for the connectors on the back. This is the module that houses the connector that interfaces with the vehicle harness, and at first glance it appears that you can tell which wires serve what function by this pinout. This is not quite correct... the pinout on this particular unit has two pins switched around: #3 and #5. All other pins are labeled correctly. Keep this in mind if you wish to power up this pair of units outside the vehicle. I was lucky enough to have access to the vehicle wiring diagrams, so I was able to catch the labeling error before I applied power.
Note the red arrow above - this indicates one of the catches that holds the faceplate on. If you intend remove the faceplate, you will need to release this. On the bottom of the amp/EQ unit, we find another arrow indicating another plastic catch for the faceplate.
In order to get this module apart, we need to be aware of a few screws on each side. Red indicates the faceplate screws. These are shorter than most of the others, and must be kept track of. Screws that are too long will damage the LCD assembly on this module.
The blue screws are for the heatsinked side panel. While four are visible on each side, there are in fact six of them. I'll show you the other two momentarily - the faceplate and faceplate PCB (circuit board) need to come out before you can access those.
All screws inside this unit are Phillips type. Most are #2 size, with many being #1 as well. Additionally, some screws inside the cassette module are #0.
Again, blue is for the heatsinked side panel, red is for the faceplate.
This is the back panel, showing the big black factory harness connector and its accompanying fuse. You can also see the round multi-way connector that the control/cassette module plugs into on the upper right.
We have a few more screws to discuss. Blue indicates the top panel screws. Green is for the harness connector assembly. You'll need to remove those to remove the harness connector and its daughterboard. Red is for the bottom panel screws.
Before we get into the body of the module, we'll remove the faceplate. This will allow the top and bottom panel to come off easily.
I've indicated four screws in red, here. These hold the faceplate PCB to the housing. We'll be taking those out in a bit.
First, let's take the top cover off. Immediately, you are able to access the solder joints on the upper circuit board of the module. This is the board all the amplifier chips attach to.
Already, I can see more than a few bad solder joints in there. In fact, I see so many of them that I'm going to just re-solder the entire board.
Turning the module over, we'll remove the bottom cover to expose this view of the lower circuit board. This board contains most of the logic for the equalizer, balance, fader, and other related functions. We will need to remove it to check the solder joints underneath.
Unplug all connectors, noting where they go. There are six of them. Then, remove the screws arrowed in red. You can't quite see the upper two due to the camera angle, but they're there.
Now, get your soldering iron and de-solder the joint indicated in blue. This is the ground wire for the housing. Just touch the iron to the joint and gently pull the wire out. You can then gently remove the board.
Here's the board, removed from the module. As you can see, it is full of components major and minor. Note the discolored areas around the capacitors in the middle... this is old heat damaged glue. Try to clean as much of that up as you can, if it's this badly discolored.
This is the underside of the board, and it is full of bad solder joints. Again, I will re-solder the entire board.
Thus far, I've already seen more bad solder joints than any other automotive head unit I've ever worked on.
This is what the module looks like with that bottom board out. You can see the amplifier chips lining each side, two per side. Fortunately, it is possible to do most repairs without removing this circuit board, so I will refrain from going that far into the unit. We've still got a lot of ground to cover.
Now that the lower circuit board has been removed, we can remove the faceplate board and insulator. Remove those four screws I showed you earlier.
Here's a shot showing the board and insulator, as well as the four red arrowed screws I mentioned that help to hold on the side panels. You will need to get at least this far into the unit to replace any of the amplifier chips, because the sides have to come off to access them.
The LCD displays on this unit are backlit by traditional incandescent lamps. They, as well as all the green sleeved illumination bulbs, all run at nine volts throughout both modules as far as I am able to tell.
If you should need to re-lamp the LCD displays on either module, I'll show you how to do it. Here's a picture of the backside of the faceplate board. The lamps are indicated in blue.
To properly replace these, you must remove the metal housing of the LCD display itself. Red arrows indicate the twist tabs that hold it to the board.
Be very careful once you release these and go to remove the metal housing. Without that housing, all the LCD components will just be sitting there, secured by nothing but the solder joints. There are various layers to the display, some of which will now be free to slide right out of the whole assembly. You don't want that. Take your time, and insure that you are very careful to keep the edge with the long line of solder joints pointed down as you move the circuit board around. This will keep all the layers in place and allow you to re-lamp the assembly.
On the outer edge, you can even replace the lamp without removing the metal LCD housing. Just gently bend the end away from the unit far enough to access the lamp. You must still remove the whole housing to access the bulb on the other side, but this side is relatively easy.
De-solder the lamp leads, and pull it right out of there.
Some of you are probably wondering where to find replacements for these lamps. To be honest, I don't know... I have not located a source for them. Most of you will likely have to jury rig some other lamps in there instead.
Here, I am using a 5mm wide lamp to replace the dead one. This is not the correct part for the job, but it serves to show you the way to do it. Ideally, you would want to use the same 3mm grain of wheat bulbs used for the illumination, because these 5mm jobs are slightly too big to fit the metal housing back on properly. They also cause potential issues with the faceplate screw in this area.
And remember - these are all 9 volt bulbs (actually, 10.7 volts as measured by my multimeter). If you use 12 volt lamps, as I have done here, the LCD display will be too dark to see well in the daytime.
Before we go on to the control/cassette module, here's a look at one of the amp chips. This is the same Hitachi HA13121 used in many other Mitsubishi built decks, including the Infinity II and Infinity III.
It's about time we had a look at the main control module. The top panel contains no screws or anything else worth noting. The bottom panel has the label, serial number, and some specs.
I'll now show you the screws worth paying attention to.
The above two pictures show you each side panel. Red arrows indicate the faceplate screws, orange arrows indicate the top and bottom cover screws.
I'm going to remove them all, because I am certain that several hundred more bad solder joints within await my iron.
This is the rear panel of the main module. A red arrow indicates a hole with a missing connector. Presumably, this is for the optional CD player interface.
The blue arrow indicates the clamp screw for the interface harness that runs to the amp/EQ module. We will not need to remove this.
Orange arrows again indicate the top and bottom cover screws.
Finally, the green arrow points to a screw that holds in the antenna jack. This is another one we will be leaving in place.
A look at the harness connector that plugs into the amp/EQ module. If you are servicing this unit, it's wise to shoot this connector with some contact cleaner and plug it in a couple times to clean it.
First things first - remove the faceplate. Then, remove the top cover.
Once the top is off, you are presented with this nightmarish scene. Servicing the amp/EQ was, in fact, the easy part.
We have a pile of arrows to discuss, so we might as well get on with it. Red arrowed screws bolt the cassette module to the housing. Blue arrowed ones secure the daughterboard retainers to the housing. Yellow arrows indicate the cassette module harness connectors. Lastly, green arrows indicate the daughterboards themselves.
All three of these daughterboards are literally plugged into the mainboard using connectors to facilitate removal. We will be removing them all to inspect their solder joints. Don't worry - they will only go back into the unit in their proper locations.
Before we mess around with removing the various parts, let's turn the unit over, pull the bottom cover off, and inspect the solder joints. And yes, I do see way too many bad joints again.
It is not necessary to remove the mainboard for our purposes, but it can be done. Simply de-solder the tabs arrowed in red to do so.
Note the orange ribbon cables near the bottom of the picture - these join the mainboard to the faceplate board. Be careful with those, because they will pull right out of their connectors with the slightest of force. I'd rather see you release the catches on those connectors first, otherwise you could damage the ribbon cables. We don't want that.
Let's turn the unit over again and remove the cassette module.
After removing the four screws and unplugging the four connectors, the module lifts right out.
Say, does this view look familiar to you?
In fact, the cassette module is a variation on the exact same one used in the Infinity II and Infinity III. Accordingly, it is every bit as problematic. And no, you cannot swap an Infinity II cassette module into this head unit. The electronics are entirely different.
And that's a shame, because this particular cassette module is totally dead. It will register a cassette being inserted - in other words the deck will switch into cassette mode - but the tape won't load and the motors won't spin. When I attempted to remove the circuit boards to inspect them, one of the ribbon cables literally tore in half.
This is one of the big reasons I tend to steer people away from these overly complex decks built by Mitsubishi in the 80s. If it's not the multitude of bad solder joints that gets you, it's this ultra finicky cassette module.
Here's a top down view of the control module without the tape deck in it. Now, we can remove the faceplate board and have a look at the LCD illumination.
The ribbon cables and their connectors up close. Release the catches on the connectors by snapping them forward, in the direction of the red arrows. I've already released one to show you how it's done.
Now, remove the four screws arrowed in red, and remove the board and insulator as an assembly.
Unsnap the black insulator from the board.
Accessing the illumination lamps for the LCD works the same way as it did on the amp/EQ module. Release the tabs arrowed in blue.
Note the orientation of the long line of solder joints between the two bottom arrows. You will again need to make sure this side faces down when you are moving the board around, because you don't want pieces of the LCD falling out on you.
The housing for the LCD won't come off just yet. You have to come around to this side, and bend the area arrowed in red outwards. There is a similar catch you will have to bend away on the other side.
Ever so gently, remove the housing to expose the bulbs.
The red arrow indicates one of the two bulbs. While these were relatively easy to replace on the big LCD panel in the amp/EQ module, these are smaller and much more difficult to deal with. You will need to use the 3mm size grain of wheat bulb for sure, as there is literally no room for the 5mm variety.
Presumably, these also run at nine volts, but I am unable to tell. No voltage is being supplied to them on this module, for reasons I have not been able to determine. The green jacketed illumination bulbs do work, however, and were measured by the meter at just under nine volts.
It's time to look at the three daughterboards that plug into the mainboard. This one houses some of the cassette control circuitry, including the DNR noise reduction, and is located right beside the cassette module.
Note that there is a plastic insulator that goes behind this board, separating it from the board we're going to look at next. Make sure you put that insulator back in correctly.
In the above two shots, you see the other daughterboard that fits in beside the cassette module. This is the one that fits closest to the side panel of the whole unit, and the one that plugs into the wiring that goes to the amp/EQ module. There are numerous bad joints here to deal with, again.
Note the discolored glue around the black relay - again, I'll be scraping as much of that off as I can.
Also note the missing components on the right side of the upper picture. This is likely where some of the switching circuitry would go if the deck were equipped with the CD player interface.
Finally, these two shots show the tuner daughterboard. This is the one found directly behind the cassette module, and once again I have a board full of bad joints to touch up.
Do you remember how all this goes back together? Good.
This concludes my look at perhaps the most overly complicated deck I've ever seen come out of an 80s or 90s Chrysler related product. I would love to be able to tell you that I was able to fully repair this one, but - with apologies to Bob - after ten hours of work, sadly this is not the case. I have been able to get it working in tuner mode, but the cassette module remains dead, the amplifier section still has issues, the LCD illumination is intermittent on the control module, and it needs brighter LCD bulbs on the amp/EQ module.
My best advice to people working with this deck... get yourselves a parts deck as soon as you can. A great deal of the parts used in this deck are impossible to find these days, and the cassette module isn't worth trying to fix if you can find a parts deck with a working one. If you have the ability, consider modifying the LCD displays to use ultra bright LEDs as well. This may hinder the unit's ability to dim the displays for night driving, but you won't want to have to replace those lamps ever again after you've done so once.
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